I've yet to find a girl who can successfully ovulate at size 0. Or climb stairs.fix-the-spade said:But I have yet to meet anyone who looked good at size 36.
I have heard a story about why there are a lot of size 0s though. Possibly apocryphal but here goes.
When women reach a certain size by dieting, they no longer have the ability to ovulate. Basically their periods stop, (And are ready to go as soon as you regain that weight) because of this they stop producing as much estrogen, and switch to testosterone.
This doesn't have the apple growing effect usually because there's not enough energy to fuel changes, but it does mean that the woman don't give off estrogen - and are less likely to be attracted to blokes.
Which is interesting, because there are a LOT of female/gay male fashion designers, who are quite happy dealing with models that are thin (like they want to be), don't have that time of the month and are producing testosterone instead of estrogen.
Whether it's true or not, I couldn't say - but it does seem to fit with something that appears to be against the image of a straight male population - who are fascinated with boobs and butts.